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9.2: Types of Molecular Bonds

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  • Graph of energy in eV versus separation in nm. The curve starts at an x value of around 0.1 and a y value of between 3 and 4. The first branch dips down sharply till x equal to 0.236 nm and y equal to 4.26 eV. From the trough, the second branch rises gradually and almost evens out just above y equal to 0. The curve crosses the x axis at 0.941 nm. The area bounded by the curve is shaded. To the right of the first branch of the curve is another curve labeled Pauli repulsion. This is cut off at y = 0 and x approximately equal to 0.3. A third curve, has a slope, which is similar to the second branch of the first curve and is below it. This is labeled Coulomb potential. A horizontal line at y equal to 1.52 is labeled ionization minus electron affinity is equal to 1.52 eV.
    Figure \(\PageIndex{3}\), we expect the bonding angle for H—O—H to be 90°. However, if we include the effects of repulsion between atoms, the bond angle is 104.5°. The same arguments can be used to understand the tetrahedral shape of methane (\(CH_4\)) and other molecules.


    • Samuel J. Ling (Truman State University), Jeff Sanny (Loyola Marymount University), and Bill Moebs with many contributing authors. This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).